Dynamic magnetic properties of Ni₂FeGa Heusler alloy nanoparticles

Here, the high-quality single crystal Ni₂FeGa nanocrystallines with γ phase or L2₁ phase were successfully synthesized by using high-temperature hydrogen reduction method and adjusting the content of salt ions and the dynamic magnetic properties of them have been investigated. The expansion coefficient of L2₁ phase nanocrystallines was determined to be as high as 1.06×10⁻⁵ K⁻¹ and the temperature-dependent damping factors be 0.0118 to 0.0234 in the temperature range 150–330 K. The results of dynamic magnetic properties revealed that the number of phonons increases with the temperature increase, which leads to the decrease of relaxation time τ and increase of the damping factor. Meanwhile, the temperature-dependent dynamic magnetic properties of L2₁ phase Ni₂FeGa nanocrystallines showed that there is no obvious change in the effect of crystal field on the freezing of angular momentum of magnetic elements of Ni and Fe ions in the range of 100–300 K. Due to the easily adjustable shape, composition, and magnetization, the Ni–Fe–Ga nanoparticles have excellent microwave absorption properties in wide frequency range, which is a potential microwave absorption material.